Wilbur: HTTP Client

URL API
HTTP Stream API
Date Input and Output

1. URL API

The URL object API exists for the benefit of the HTTP client code; other parts of the toolkit (the XML and RDF parsers) represent URLs as strings.

make-url (string) [Function]

Parses the URL in string (a string) and returns an url instance (the class url is abstract, an instance of some subclass is returned). The function will signal malformed-url if the parsing fails.

url [Class]

Abstract base class of URLs.

url-string (url) [Generic function]

Returns a string rendition of the URL.

url-path (url) [Generic function]

Returns the path component of the URL (as a string).

file-url [Class]

Concrete class (subclass of url) of file-URLs (these URLs only have a path component). Do not instantiate this class directly, instead use make-url.

http-url [Class]

Concrete class (subclass of url) of http-URLs (these URLs have a host and a port component in addition to the path component). Do not instantiate this class directly, instead use make-url.

url-host (http-url) [Generic function]

Returns the host component of an http-url instance (as a string).

url-port (http-url) [Generic function]

Returns the port component of an http-url instance (as an integer).

2. HTTP Stream API

In the current version of Wilbur the HTTP streams functionality is only avaible on the Macintosh Common Lisp (due to the fact that open-http-stream uses an MCL-specific implementation of the socket interface).

open-http-stream (url proxy) [Generic function]

Opens and returns a bidirectional stream for requesting the URL url (an instance of some subclass of url), possibly via the HTTP proxy proxy (an http-url instance).

open-http-stream ((url http-url) (proxy null)) [Method]

An implementation of open-http-stream for regular HTTP URLs without an HTTP proxy.

open-http-stream ((url http-url) (proxy http-url)) [Method]

An implementation of open-http-stream for regular HTTP URLs with requests going through an HTTP proxy. Proxies are specified as HTTP URLs, the system will merely ignore any path component.

http-message [Class]

This class represents HTTP response messages.

http-status (http-message) [Generic function]

Returns the status code of the HTTP response (as an integer).

http-version (http-message) [Generic function]

Returns the version string of the HTTP response.

http-headers (http-message) [Generic function]

Returns an a-list (in the string dictionary format) of HTTP response headers.

http-body (http-message) [Generic function]

Returns an open input stream which, when read, will yield the body of the HTTP response to "GET".

get-header (http-message header) [Generic function]

Returns the HTTP header named by the string header from the HTTP response http-message (an http-message instance), or nil if no header with that name is found.

http-head (url &key proxy) [Generic function]

Performs an HTTP "HEAD" request to the URL url (possibly via the HTTP proxy proxy), and returns an HTTP response (an instance of http-message). The response has a null body, i.e. the function http-body will return nil.

http-get (url &optional proxy) [Generic function]

Performs an HTTP "GET" request to the URL url (possibly via the HTTP proxy proxy), and returns an HTTP response (an instance of http-message). The body of the response can be read from an input stream which can be accessed via the function http-body.

with-http-response ((response body-input-stream url &optional proxy) &body body) [Macro]

Performs an HTTP "GET" request to the URL url (possibly via the HTTP proxy proxy), and for the execution of the forms in body binds the variable response to the HTTP response object (an instance of http-message) and the variable body-input-stream to an input stream which will yield the response body (see the function http-body for an explanation). Regardless of how the execution of body ends, the input stream is closed on exit.

3. Date Input and Output

parse-http-date (string) [Function]

This function parses the string string according to the date syntax(es) specified in RFC 2616 (HTTP/1.1):

RFC 1123
RFC 850 (with the assumption of 21st century)
ASC Time

The parser is non-dogmatic about the formats, and merely returns nil if it detects something in such violation of the standards that it would make reliable parsing impossible. Successfully parsed time is returned in the Common Lisp universal-time format.

parse-iso8601-date (string) [Function]

This function parses the string string assuming it contains an ISO 8601 -formatted date. Successfully parsed time is returned in Common Lisp universal-time format; otherwise nil is returned.

iso8601-date-string (universal-time) [Function]

This function takes an integer universal-time (assumed to contain a date in universal-time format) and returns a string with the date formatted according to the ISO 8601 standard. The current time zone is assumed.